Question MSI motherboard debug light questions

Jan 21, 2023
Hi! Long time lurker, but now I need some help so here I am.

I built a new PC
Psu: Corsair rm850x
GPU: Rx 6800xt
Cpu: ryzen 5600x
Mobo: MSI b550 tomahawk
Ram: Corsair vengeance 2x8gb (2400mhz from an old build, with a 3000mhz known working tester after)
Storage: Samsung 980 pro

Something weird happened while I was installing windows, I made it the part where you get a black screen that says "hi". Then the PC just shut itself off and restarted. I was then greeted with the 'MAG' splash screen with "starting automatic repair"

That lasted for 5 hours before I switched off the PC. When I switched it back on the weirdness started.

On power on, I would see the cpu debug light turn on for a second, the dram light would turn on for a fraction of a second, and then that was it. Fans would spin, RGB would shine, but I could no longer boot to bios.

If I remove all the RAM, I get the solid DRAM light shining. Makes sense. I tried moving each DIMM into each RAM slot (single and together) and got the same result

If I remove the GPU (VGA is the next debug light after dram) the mobo doesn't light up the VGA debug light. This suggests that the problem is either the RAM or the GPU. But I borrowed some known working RAM, and we just couldn't get past the light.

So! Does anybody have any idea what's going on? Did I manage to Bork something by having the audacity to install windows? Did I get a motherboard that just didn't want to carry on?

Pre-requisite "this isn't my first build" but I'd love to hear any thoughts you experts might have. :)